Question

Q1) Identify the control variable,Manipulated variable and Disturbance variable in the experiment set-ups below

1.Pressure process control

2.Cascade controller

3.Interacting and non interacting tank

Q2) When you used a PID control for flow control system with PB = 50, τI = 0 and τD = 0, do you expect to see an offset? explain

thankyou❤️

Answer 1

Q1.

1. in pressure process control (used to fluid stream) pressure

controlled variable = valve outlet pressure

Manipulated variable= air flow rate on top of diaphragm that affect opening of the valve

Disturbance variable= pressure at valve inlet

2.In cascade controller (assuming jacketed tank process)

controlled variable = tank temperature

Manipulated variable = jacket cooling water flow rate

Disturbance varible=input stream flow rate in the tank

3.Controlled variable =Level height

Manipulated variable = output flow rate

Disturbance = inlet flow rate

Q2. Since _D=0 (no derivative action) i=0 (maximum integral action as 1/i=infinity) so it behaves like PI Controller so offset nearly zero or very minimum.